A series of new composite materials based on Fe₃O₄ magnetic nanoparticles coated with SiO₂ (or aminated SiO₂) were synthesized. It has been shown that the use of N-(phosphonomethyl)iminodiacetic acid (PMIDA) to stabilize nanoparticles before silanization ensures the increased content of a SiO₂ phase in the Fe₃O₄@SiO₂ nanocomposites (NCs) in comparison with materials obtained under similar conditions, but without PMIDA. It has been demonstrated for the first time that the presence of PMIDA on the surface of NCs increases the level of Dox loading due to specific binding, while surface modification with 3-aminopropylsilane, on the contrary, significantly reduces the sorption capacity of materials. These regularities were in accordance with the results of quantum chemical calculations. It has been shown that the energies of Dox binding to the functional groups of NCs are in good agreement with the experimental data on the Dox sorption on these NCs. The mechanisms of Dox binding to the surface of NCs were proposed: simultaneous coordination of Dox on the PMIDA molecule and silanol groups at the NC surface leads to a synergistic effect in Dox binding. The synthesized NCs exhibited pH-dependent Dox release, as well as dose-dependent cytotoxicity in in vitro experiments. The cytotoxic effects of the studied materials correspond to their calculated IC₅₀ values. NCs with a SiO₂ shell obtained using PMIDA exhibited the highest effect. At the same time, the presence of PMIDA in NCs makes it possible to increase the Dox loading, as well as to reduce its desorption rate, which may be useful in the design of drug delivery vehicles with a prolonged action. We believe that the data obtained can be further used to develop stimuli-responsive materials for targeted cancer chemotherapy.

( R )-2-Phenoxypropanoate ester was efficient chiral resolving agent in acylative KR of racemic cyclic alkylamines; highest selectivity was observed for 2-methylpiperidine with predominant formation of ( R , R )-amide, which was confirmed by DFT modelling.

The review summarizes data on the synthesis methods and properties of 4-amino-5-oxoproline derivatives, including those with substituents at the amino and/or carboxyl group, carbon skeleton atoms, as well as peptides incorporating a 4-amino-5-oxoproline fragment. Particular attention is paid to the synthesis methods of the individual stereoisomers of derivatives of this amino acid, which serve as starting materials for constructing more complex structures such as peptidomimetics, etc. 4-Amino-5-oxoproline derivatives exhibit a variety of biological activities: antitumor, immunomodulatory, psychotropic, etc., and are of interest for the development of new therapeutic agents based on them.